HibernateBean Manager

[ekobir]

Hi Bruno

I think there is a small problem in the new hibernate bean manager.... holdPersistentObject method in the Hibernate bean manager checks the property assaignability against  Collection and map (with isAssignableForm)

and then if this case(isCollection variable) is false, it checks another instanceOf against collection and map
in the body of if condition.

if ((ClassUtils.immutable(propertyClass) == false) &&
                    (ClassUtils.isJavaPackage(propertyClass) == false) &&
                        (isCollection == false)) ------> I think this is a problem...
                {

Thanks
Erkin

[Bruno Marchesson]

Hi Erkin,

Did you have a look at release 1.1.1 ?
Here is the holdPersistentObject method :
"protected boolean holdPersistentObject(Object pojo)
    {
        try
        {
        //    Precondition checking
        //
            if (pojo == null)
            {
                return false;
            }
           
            if (_persistenceUtil.isPersistentPojo(pojo) == true)
            {
                return true;
            }
           
        //    Iterate over properties
        //
            BeanInfo info = Introspector.getBeanInfo(pojo.getClass());
            PropertyDescriptor[] descriptors = info.getPropertyDescriptors();
            for (int index = 0; index < descriptors.length; index++)
            {
                PropertyDescriptor descriptor = descriptors[index];
                Class<?> propertyClass = descriptor.getPropertyType();
                if ((ClassUtils.immutable(propertyClass) == false) &&
                    (ClassUtils.isJavaPackage(propertyClass) == false))
                {
                //     Not a basic type, so a check is needed
                //
                    // Get property value
                    Method readMethod = descriptor.getReadMethod();
                    readMethod.setAccessible(true);
                    Object propertyValue = readMethod.invoke(pojo, (Object[])null);
                   
                    if (propertyValue == null)
                    {
                        continue;
                    }
                    // Get real property class
                    propertyClass = propertyValue.getClass();
                   
                    if ((_classMapper != null) &&
                        (_classMapper.getSourceClass(propertyClass) != null))
                    {
                        propertyClass = _classMapper.getSourceClass(propertyClass);
                    }
                   
                    if (_persistenceUtil.isPersistentClass(propertyClass) == true)
                    {
                        return true;
                    }
                   
                    // collection and recursive search handling
                    if (propertyValue != null)
                    {
                        if (propertyValue instanceof Collection<?>)
                        {
                        //    Check collection values
                        //
                            Collection<?> propertyCollection = (Collection<?>)propertyValue;
                            for(Object value : propertyCollection)
                            {
                                if (holdPersistentObject(value) == true)
                                {
                                    return true;
                                }
                            }
                        }
                        else if (propertyValue instanceof Map<?, ?>)
                        {
                        //    Check map entry and values
                        //
                            Map<?,?> propertyMap = (Map<?, ?>) propertyValue;
                            for(Map.Entry<?, ?> value : propertyMap.entrySet())
                            {
                                if ((holdPersistentObject(value.getKey()) == true) ||
                                    (holdPersistentObject(value.getValue()) == true))
                                {
                                    return true;
                                }
                            }
                        }
                        else
                        {
                        //    Recursive search
                        //
                            if (holdPersistentObject(propertyValue) == true)
                            {
                                return true;
                            }
                        }
                    }
                   
                }
            }
           
            // No persistent property
            return false;
        }
        catch (Exception e)
        {
            throw new InvocationException(e);
        }
    }"

Does it look ok to you ?

Regards
Bruno

[ekobir]

Hey Bruno

Thanks for your help again...  One more question,  Is latest version of the code always in trunk?

Thanks
Again

[Bruno Marchesson]

Hi,

The current release code is in branch '1.1'.
The trunk contains the code of the upcoming release (1.2), which has been fully refactored (I rewrote the whole proxy informations handling, and added some new features).

Regards
Bruno

[ekobir]

Hi Bruno

It is really good info for me as I will not continue trying to build trunk....  Unfortunately (unfortunate because I don't want to disturb you.) I have one more question.

When I try to send one of my domain object to client side, I'm getting security exception because of java assist proxy implementation. (host mode is working fine, but problem occurs on app server)

But I got actually another error before that while hibernateBeanManager is cloning the object.

PropertyDescriptor for javassist.util.proxy.MethodHandler in the generated class does not have any getter method for Method handler.  So

"Method readMethod = descriptor.getReadMethod();" call in the holdPersistentObject method returns nulls and I'm getting null pointer exception.

I put a simple hack as a work around but it didnt solve my security exception problem.

Caused by: com.google.gwt.user.client.rpc.SerializationException: Type 'My_Domian_Object_$$_javassist_3' was not included in the set of types whic
h can be serialized by this SerializationPolicy or its Class object could not be loaded. For security purposes, this type will not be serialized.

Thanks your help...

[ekobir]

Hi Bruno

Finally, I think I found a workaround for my problem. Let me explain you
what happened.

I'm trying build a system which is using gwt 1.5.2, hibernate
3.2.6.ga, Spring 2.5.5,  hibernate4gwt1.1.1, gwt-sl 0.1.5a basically
latest version of everything. (As project is not live yet, I would
like to keep up with the release)

The problem(it might be known but i wasnt aware) was getting an
object ,which is enabled for lazy loading, from server side to client
side.

E.x

class Service{
   Set<Contract> contracts;

}

class Contract{
     Service service;
  // Basic types and their getter setter

}

as you can see, there is a bidirectional relationship between Service
and Contract. So hibernate-mapping settings in the Service.hbm.xml is
like below

<set name="contracts" inverse="true" lazy="true" cascade="all">
            <key column="serviceId" not-null="true" />
            <one-to-many class="myDomain.Contract"/>
</set>

The business scenario is getting all of contracts for a specific
serviceId.
Implementation at the server side was exactly what it is shown at
http://www.hibernate.org/328.html

so My generic DAO had following method.
@SuppressWarnings("unchecked")
    public T findById(ID id, boolean lock) {
        T entity;
        if (lock)
            entity = (T) getSession().load(getPersistentClass(), id,
LockMode.UPGRADE);
        else
            entity = (T) getSession().load(getPersistentClass(), id);

        return entity;
    }

and My business method was

Service getContracts(int serviceId){
    Service service = this.findById(serviceId, false);
    if (service != null) {
       Set<Contrat> contracts= service.getContracts();
       contracts.size(); //Note: this is a temporary solution to
prevent JRE code optimization before going to production.
    }

    return service;

}

At this point getContracts method returned Service_javasisst as it is
in the pre email..... And hibernate4gwt was not able to clone this
object before serialization for RPC by throwing the exception in the
previous email.

In order to fix the problem, I changed load calls in the findById with
get calls.

@SuppressWarnings("unchecked")
    public T findById(ID id, boolean lock) {
        T entity;
        if (lock)
            entity = (T) getSession().get(getPersistentClass(), id,
LockMode.UPGRADE);
        else
            entity = (T) getSession().get(getPersistentClass(), id);

        return entity;
    }

So Only thing I need to be aware is not to expect HibernateException
for unknown ids instead I need to do null checking on the returning
obj.

Thanks
Erkin

[ekobir]

Last Note:

I just forgot to add the cause of this difference. If you look at the code in the

org.hibernate.event.LoadEventListener.java, you will see the difference between GET LoadType and LOAD LoadType

public static final LoadType GET = new LoadType("GET")
            .setAllowNulls(true)
            .setAllowProxyCreation(false) --> important
            .setCheckDeleted(true)
            .setNakedEntityReturned(false);
   
    public static final LoadType LOAD = new LoadType("LOAD")
            .setAllowNulls(false)
            .setAllowProxyCreation(true) --> important
            .setCheckDeleted(true)
            .setNakedEntityReturned(false);

Thanks
Erkin

[Bruno Marchesson]

Hi Erkin,

I really think that Hibernate "session.load" is pretty useless, except on very specific case, because it creates a uninitialized proxy that will lead to lazy loading on first access.
Nevertheless, I consider the exception thrown on proxy as a bug and will try to fix it ASAP.

Regards
Bruno

[ekobir]

Hi Bruno

Thanks for your consideration...  I'm ready to help as well.

Erkin